This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This translational research project is prompted by the need to develop new evaluative tools to assess the preclinical safety of tissue engineered biological heart valves intended for use in infants, children and young adults. This design will test the safety of the acellular construct and the immunogenic and proinflammatory potential of allograft (papio) versus xenograft (human) structural proteins. The initial implants will be constructed as decellularized scaffolds. Development of such a relevant primate model should facilitate the extension to clinical studies for any putative tissue engineered cardiovascular construct. Specific Aim: Explore the feasibility of developing chronic baboon models of open heart valve replacement surgeries for the evaluation of biological heart valve. The utility of conducting such studies in baboons will be determined by comparison to control biological and bioprosthetic (cryopreserved allograft and xenograft bioprosthetic manufactured) valves that already have had extensive preclinical testing and worldwide clinical experience.